Sinosenecio tongziensis R. B. Zhang, Tan Deng & Ying Liu, 2025

Sinosenecio tongziensis R. B. Zhang, Tan Deng & Ying Liu sp. nov.

Figs 1 View Figure 1 , 2 View Figure 2

Type.

China • Guizhou Province, Tongzi County, Guancang Town, Xianrenshan Mountain , elev. 1,200–1,300 m, growing on slopes beneath forests in karst areas, 27 April 2020, Chong-Bo Ma ZRB 1607 (fl.) (holotype: ZY!; isotype: PE!) , • 5 May 2024, Ren-Bo Zhang ZRB 2661 (fl.) (paratype: ZY!, SCFI!) , • 25 May 2024, Ren-Bo Zhang ZRB 2676 (fr.) (paratype: ZY!) .

Diagnosis.

Resembles S. changii in the subscapigerous habit, ovate-oblong and pinnately veined leaf lamina, and simple to compound terminal corymbs, but differs by membranous leaf lamina (vs. papery), 8–10 lateral veins (vs. 10–18), and stems and leaves pubescent with 2–5 mm long, uniseriate, spreading hairs (vs. sparsely white arachnoid to densely white tomentose) (Table 1 View Table 1 ).

Description.

Herbs, scapigerous. Fresh rhizomes 6–16 mm in diam., clad in persistent brown petiole bases. Stems 1 to 3, erect, scapiform, 15–40 cm tall, ribbed, villous with 2–5 mm long, uniseriate, spreading hairs. Leaves several, radical, rosulate, densely villous as the stems; petiole 3–9 cm long; blade (broadly) ovate, obovate, or ovate-oblong, 4–14 × 3–10 cm, membranous, villous, densely so along veins, pinnately veined, lateral veins 4–5 pairs, base cordate, margin repand with mucronulate teeth, long ciliate. Capitula 4–29, arranged in terminal simple to compound corymbs; peduncles 1–5 cm long, slender, (sparsely) pubescent, with 3–20 mm long, linear or linear-spatulate bracts. Involucres campanulate, 4–7 × 4–7 mm, not calyculate; phyllaries ca. 13, lanceolate, oblanceolate or subelliptic, 4–6 × 1–1.6 mm, herbaceous with membranous margins, abaxially pubescent with uniseriate, spreading hairs, apically acuminate, ciliate at the apex and on upper margin. Ray florets 10–13; corolla tube 2.5–3.5 mm long, glabrous; ray yellow, oblong, 7–10 × 1.2–2.2 mm, 4 - veined, apically 3 - denticulate. Disk florets many; corolla yellow, 4–6 mm long, with 2–3 mm tube and campanulate limb; lobes ovate-lanceolate, ca. 0.8 mm long, apically acute. Anthers oblong, ca. 1.1 mm long, base obtuse to rounded, appendages lanceolate. Styles ca. 2.5 mm long in ray florets and 4–4.5 mm long in disk florets, branches recurved, ca. 0.8 mm long. Achenes cylindric, 1.6–2.0 mm long, inconspicuously ridged, glabrous. Pappus capillary-form, uniform, white, persistent, 2.4–4.0 mm long.

Floral micromorphological characters.

The filament collar of S. tongziensis consisted of uniformly sized cells (Fig. 3 E View Figure 3 ), and the anther endothecial cell wall thickenings were polarized and radial (Fig. 3 F View Figure 3 ), lending strong support for the phylogenetic affiliation of S. tongziensis in subtribe Tephroseridinae (see below).

Phenology.

Flowering from April to May, fruiting from May to June.

Etymology.

The specific epithet is derived from the type locality, Tongzi County, Guizhou Province, China.

Vernacular name.

The proposed Chinese name is “ 桐梓蒲儿根 ”, pronounced as “ tóng zǐ pú ér gēn ”.

Distribution and ecology.

The new species is endemic to Guizhou Province and is currently known only from the type locality, Xianrenshan Mountain, Tongzi County. It grows on slopes beneath the forests in karst areas at elevations of 1,200 –1,300 m.

Conservation status.

Sinosenecio tongziensis is currently recorded only at the type locality. Thousands of individuals are scattered across the mid-slope and at the base of the mountain, with approximately 600 to 700 mature individuals. Given its narrow distribution and relatively low number of mature plants, S. tongziensis may be more appropriately categorized as vulnerable (VU) according to the IUCN Red List Categories and Criteria ( IUCN Standards and Petitions Committee 2022).

Phylogenetic affiliation.

In the phylogenetic tree, Nemosenecio and Tephroseris were resolved as monophyletic (Fig. 4 View Figure 4 ). Together with some species of Sinosenecio , these genera constituted a well-resolved clade representing subtribe Tephroseridinae (Fig. 4 View Figure 4 ), conforming to previous studies ( Wang et al. 2009; Ren et al. 2017; Zou et al. 2020). Despite its close resemblance to S. changii , S. tongziensis instead formed a weakly supported lineage (PP = 0.6) with S. bodinieri (Vaniot) B. Nordenstam , S. confervifer (H. Léveillé) Y. Liu & Q. E. Yang , S. nanchuanicus Z. Y. Liu, Y. Liu & Q. E. Yang , and S. globiger var. adenophyllus C. Jeffrey & Y. L. Chen (Fig. 4 View Figure 4 ). It can be easily distinguished from these related species by the pinnately veined leaves (vs. palmately).